Electrostatic air cleaners use electric energy to generate electrostatic forces which create air flow without the use of a fan or other moving parts. Electrostatic forces also enable the air cleaner to collect airborne contaminants such as dust, smoke, oil mist, pollen, pet dander and other small debris particles from the air circulated in dwellings, workplaces, and other structures. Generally, known electrostatic air cleaners utilize two arrays of electrodes excited by high-voltage. In a known design, the first electrode array comprises wire or rod-shaped electrodes (hereinafter “wire electrodes”), while the second electrode array comprises plate electrodes. A high-voltage generator creates an electrical charge between the first and second electrode arrays.
The particulate matter enters the region of the first electrode array and is charged before entering the region of the second electrode array, where it is removed from the air stream. Specifically, due to the high-voltage charge at the wire electrodes, free electrons are stripped off of atoms and molecules in the surrounding air. These electrons migrate to the positively charged wire electrodes, where they are collected. The removal of free electrons leaves the stripped atoms and molecules positively charged, which are repelled from the positively charged wire electrodes and attracted to the negatively charged plate electrodes. The addition of the electrons from the negatively charged plate electrodes also produces negative air ions that are propelled from the trailing edge of the plate electrodes. Thus, the ionic forces exerted on atoms and molecules create a silent movement of air through the air cleaner.
Because the plate electrodes collect the debris from the air flowing through the air cleaner, the plate electrodes need to be cleaned regularly. Typically, to clean the plate electrodes, the user removes the electrodes from the air cleaner and washes them to remove the collected debris. Warm water and a sponge may be used to facilitate the cleaning. After the plate electrodes are completely dried, they may be returned to the air purifier unit. Returning the plate electrodes to the unit while they are wet is dangerous and could cause irreparable damage to the air purifier unit. Accordingly, it is very important to allow the plate electrodes to fully dry before returning them to the air purifier unit.
FIG. 1 depicts a known electrostatic air conditioning device 100, as shown in U.S. Pat. No. 6,953,556, wherein the plate electrodes 110 are attached to a handle 120. To remove the plate electrodes 110 for cleaning, the user pulls the handle 120 up vertically, pulling the plate electrodes out of an opening 130 in the top surface 135 of the device. The handle serves two purposes: it assists the user with vertically removing the electrodes out of the housing and it covers the opening in the top surface when the plate electrodes are at rest in the air purifier.
The disadvantage of the known device 100 is that when the plate electrodes 110 are removed for cleaning, an open hole 130 remains on the top surface 135 of the air purifier 100. Leaving an exposed opening in the top surface of the air purifier for an extended period of time can be dangerous and unsightly. The air purifier includes various electronic components that are exposed and accessible through the opening 130 in the top surface 135. When the plate electrodes are removed, a child can easily reach through the hole into the unit and can cause damage to the unit or to himself. Furthermore, foreign objects can be dropped into the device, interfering with the operation of the device when it is turned on. The presence of a foreign object in an electrostatic air purifier is not only harmful to the air purifier but could be dangerous to the user, particularly if the foreign object is a metallic item that could interfere with the electrical operation of the air purifier. Furthermore, if dust or other debris gathers in the unit when the top is left open, the safety and efficiency of the unit could be affected.
Accordingly, there is a need for an air purifier having a safety cap which can be utilized to keep the unit free of dust, debris and other foreign objects while the collector blades are being cleaned.
Furthermore, there is a need to prevent access to the internal components of the air purifier unit when the collector blades to be cleaned are removed and for the duration of the cleaning.